Duration Neutral Position

This question from 2020 Curriculum, Reading 20 Question 11 of End of Chapter.

Question of EOC:
Profit from an increase in the curvature of the yield curve, so long the 2-year bonds, short the 5-year bonds, short the 10-year bonds, and long the long-term bonds. What is the amount that Hirji should allocate to the 2-year bond position?

My question is:
But why the answer given to allocate for 2-year bonds is (Money duration of long-term bonds / PVBP of 2-year bond)? I thought I should be (Money duration of 5 & 10 yrs bonds / PVBP of 2-year bond)?